For many sufferers of long Covid, proving they are sick is a big part of the battle - CNN

or the ones who were sympathetic and supportive said 'we don't know, it's a new disease and we just don't know,'" she said.

Learning that they were not alone, that other people were experiencing the same issues, was a huge revelation for both Hishmeh and Jackson.

A majority of the 700,000 said their illness was limiting their day-to-day activities and for almost 70,000, the symptoms have lasted for more than a year.

A separate study published last month showed that seven in 10 people who had been hospitalized for Covid-19 have not fully recovered five months after being discharged.

While the figures made big headlines, they did not come as a surprise to those suffering from long Covid and their doctors.

About 10% suffer long-term

Dr.

As a rehabilitation medicine expert, he knew previous epidemics of SARS and MERS left some patients suffering with post-viral syndromes a long time after the epidemics were declared to be over.

The vast number of different symptoms make long Covid a particularly worrying public health problem.

Nisreen Alwan, an associate professor of public health at the University of Southampton, said the mobilization of long Covid patients through social media helped speed up the recognition of the condition as a serious problem.

Hishmeh has co-founded Long Covid SOS, an advocacy group that campaigns on behalf of patients to get more recognition for the condition, more research into it and more support for those suffering from it.

Jackson said she's turned the corner about 10 months after getting sick.

While the experts aren't yet certain about the science on why this could be happening or how long patients' improvement might last, other Covid longhaulers have also reported relief after getting inoculated.

Second pandemic

More than 133 million people globally have been infected with coronavirus.

While it's unclear how many are suffering from long Covid, public health experts are warning of a 'second pandemic' of longhauler disease.

"The scale is enormous," said Dr.

"And the UK is wealthy compared to most countries, we're supposed to have systems in place and if we're struggling, the implications for countries that are less well off and developing is huge, I don't even think it's being recorded, we don't know how many people have it."

A study released earlier this week has shown that as many as one in three people infected with Covid-19 have longer term mental health or neurological symptoms.

She said many long Covid patients are experiencing cognitive difficulties like memory problems, speech difficulties, ability to concentrate, read or plan their day.